[editor-surveyor]

Certainly some represent extinct animals, IMO.

Obviously some of them represent many animals that are still reproducing in sufficient numbers that we recognize them. Then there are those that we once thought extinct but recently found otherwise (like the snail that lives along the shores of the Dead Sea that was once used to make blue dye for clothing).

[RightWingNilla]

My understanding is that the vast majority of fossils do not have modern day counterparts. I mean some of them kind of look like animals alive today, but there are substantial anatomical differences.

What were all of these animals, and why did they completely die off?